The present invention relates to a small-sized switch, and more particularly to improvements mainly in the contacting mechanism of the small-sized switch.
According to the prior art, in the switch of the type in which a clip-shaped moving contact is laid astride and in contact with the both sides of a plurality of fixed contacts arranged in a straight line, those fixed contacts are formed, as shown in FIG. 4 (showing an example of a slide switch), into such a plate shape (which is indicated at reference numeral 5) as is made by punching a plate.
However, the plate-shaped fixed contacts raise a problem, as is experienced in a rotary switch, for example, even in the case of a mechanism of the type in which a clip-shaped moving contact is brought into contact with a single fixed contact. Especially in case the moving contact has to be brought into simultaneous contact with two fixed contacts, as in a switch to which the present invention is to be applied, the following problems are further raised. More specifically, even if those plural fixed contacts are arranged in a row in the switch base plate, the corners (or the edge portions) of the fixed contacts act, when in the operation of the switch, i.e., when the clip-shaped moving contact is to move, to scrape the silver or the like plated on the inner sides of the aforementioned moving contact. The resultant problem is that the contacting stability is deteriorated. When those aligned fixed contacts are to be caulked to the base plate, moreover, there arises another problem that the leading end portions of the fixed contacts are inclined or slightly bent. If those fixed contacts are assembled, as shown in FIG. 5(a), the plural fixed contacts 5, 5' and 6 are not aligned but meandered. In this instance, therefore, if the clip-shaped moving contact 7 is made to clip the two fixed contacts for the switching operations, there arises a phenomenon that the moving contact abuts, in its moving course, against the near sides of the adjoining fixed contacts so that its sliding movement is blocked. As is better seen from FIG. 5(a), on the other hand, the moving contact 7 moves along one side of each fixed contact or pushes one of the fixed contacts thereby to invite another phenomenon that it absolutely fails to contact with one side of the other eccentric or bent fixed contact 5. On the other hand, since the conventional plate-shaped fixed contacts are generally formed by the punching process using a press, their respective one sides are formed with burrs so that they have high frictional resistances. Those phenomena cause that the contacting state of the moving contact with the fixed contacts is effected only at one side or at a point so that it remarkably lacks smoothness or becomes imperfect or unstable. The contacting area of the contact is so considerably reduced that the rated current capacity is not allowed to invite an accident due to the heat liberation. Likewise, an accidental insufficiency in the contacting state is invited to raise another drawback that the durability of the contacting portions is remarkably reduced.
In the conventional switch, moreover, since the plate-shaped fixed contacts 5, 5' and 6 are widthwise arranged in a row, as shown in FIG. 4, the spacing between the respective fixed contacts cannot be reduced so much as to invite difficulty in the reduction of the switch size.